Crouching gti, hidden dragon

The gti has come out of hibernation.

http://www.vwwatercooled.com.au/foru...my6snchf-1.jpg

I have been living in Japan for a little while. But the gti was not forgotten, and I returned with a little j-spec goodness for it.

http://www.vwwatercooled.com.au/foru...4mnyursv-1.jpg

This was built at the Kaaz factory just in the next prefecture from me. Kaaz are a bit of a strange company, famous for hardcore motorsport differentials, and lawn mowers. A strange combination! I wanted to pick it up in person and see the factory but they wouldn’t let me. Wouldn’t want those top-secret edge trimmer designs getting leaked..They delivered it for free though.

So, time to build up an 02J to house this baby. I found a DBZ which has the 3.68 FD ratio that best suits my setup. Apparently it had a lazy 1st-2nd syncro so it will be getting brand new syncro’s as well as new bearings. Not to mention a fancy new diff.

http://www.vwwatercooled.com.au/foru...vxyzknql-1.jpg


The Kaaz LSD is a 1.5 way clutch style LSD. It is more extreme than the current torque-biasing Peloquin I use. Much more motorsport oriented. The clutch style diffs get a bad rap for being noisy, but this one is the new “Special Q” unit which apparently go through a bedding-in and hardening pre-treatment so that chattering noise is cut right down. You don’t even have to do the figure 8 bed-in procedure like you normally do. The 1.5 way aspect is something I am really looking forward. There is partial lock-up under decel. Apparently this really stabilises the car and tends to give you more confidence to brake later into corners. We will see.. Also, no more open diff when the inside wheel gets too unloaded (which did happen at Wakefield)

I took the mk1 down to Marulan for the first time on the weekend. It’s a very tight track so you don’t get to really open it up for that long. But you have to work hard with all of the corners, and a bit of sprinkling rain throughout the day added to the challenge.

I used the opportunity to figure out which of the 2 front sway bars I have works the best for me. After changing the sway bar during the lunch break it was crystal clear to me which one was the best. A track like this was perfect for testing sway bars.

Let me guess, you went with the thinner front bar?

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Originally Posted by sports racer

Let me guess, you went with the thinner front bar?

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Nope, I went with the bigger bar :)

25mm vs 20mm. But the 25mm bar is hollow.

Here’s another session from the weekend at Marulan. I’m following a red, apparently 300kw, commodore. It was quite nimble for such a large car. He was using slicks from the Porsche cup series, one of which ended up being destroyed by a lip on one of the concrete verges.

Was your old diff a peloquin?

So your set up now 25mm front and 28mm rear?

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Originally Posted by Water Boy

Was your old diff a peloquin?

So your set up now 25mm front and 28mm rear?

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This is still the peloquin LSD, I haven't finished the new box with the kaaz yet. Hopefully it improves traction.

Yep sway bars are 25mm front and 28mm rear.

After looking at the video you must really be holding out for the new diff if it lets you put down the power earlier.

How much time per lap was the front bar worth?

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Originally Posted by sports racer

After looking at the video you must really be holding out for the new diff if it lets you put down the power earlier.

How much time per lap was the front bar worth?

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Yeah I struggle with traction. To me it feels like the peloquin is going open diff every now and then, probably when I unload one front wheel just enough. This track was a bit bumpy so that probably happened a bit. The old peloquin in the 020 was actually better than this one because it had the pre-load shims behind the flanges that meant the diff would work even with a wheel in the air. The newer peloquins don't have that. If the kaaz improves the situation it should yield a significant improvement in lap times.

I knocked a second off with the 25mm front bar, but there are too many other variables including inconsistent driving. But I could tell the car felt more balanced straight away.

Sweet looking ride dude :)

Quote:

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Originally Posted by abreut

Nope, I went with the bigger bar :)

25mm vs 20mm. But the 25mm bar is hollow.

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what is the hole size?

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Originally Posted by Notso Swift

what is the hole size?

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Wall thickness is 3.5-4mm, so 17-18mm.

The new bar will be about 90% stiffer based on 4mm wall or 75% for 3.5mm

I think once you have all the extra power train weight up front withe 16vt and the cableshift box, that bigger front bar makes a lot of sense.
Great to see it out of the den!

Its the relationship between front and rear that is important, and a 28mm rear bar is bloody stiff. If I jack the car up from the front jacking point just behind one of the front wheels, the rear wheel on that side leaves the ground before the front.

It is stiff for the street and you have to be careful in the wet, but as soon as you put semi-slicks or slicks on and get them up to temp, you need it that stiff. I have never understood all this talk about removing the front sway bar all together. If I did that the car would handle like crap. Maybe if you have really stiff suspension but that would suck on a car still driven on the street.

A belated thanks to Notso Swift for the calculations on the sway bar. Its strange how the car didn't feel that much more taily with the smaller one. Anyway the bigger one definitely feels more suited to the rest of the suspension.

Now for the gearbox build. I had to wait a while for gearbox parts, many of which came from the US, so that delayed the gearbox build a bit. But I finally finished it and I just took it for a test drive. No strange noises or anything - success!

So here are a few photos to catch up. Here’s the sorry-looking cases and the internals of the box all apart and ready for cleaning.
http://www.vwwatercooled.com.au/foru...ldyhmiwj-1.jpg
http://www.vwwatercooled.com.au/foru...lzqhkx3f-1.jpg

I ordered brand new synchros for 1st through to 4th. 2nd gear is a 3-piece synchro. I also ordered new selector hub springs and a few other bits and pieces. Oh and of course all new top quality bearings. Everything was checked over very carefully, and all shims properly sized by the book. Here are a few of the goodies, and the Kaaz lsd sitting in its new home
http://www.vwwatercooled.com.au/foru...hubt4d85-1.jpg
http://www.vwwatercooled.com.au/foru...fui2kmrg-1.jpg

Finished product
http://www.vwwatercooled.com.au/foru...wal6oiue-1.jpg
http://www.vwwatercooled.com.au/foru...kna0njsn-1.jpg

I had to modify the rear mount because the 02A I had in previously is a bit special (as are all the ones I have seen from Seat Cupras and Toledos), and different to regular 02A’s and 02J’s. The diff housings are a strange shape - apparently related to the later 4-motion setups. I also decided to finally do the mod which gets rid of the big square block, and replaces it with a round bush. gldgti and Peter Jones have done this mod too, each slightly differently. I did mine in such a way so that I can unbolt and revert back to the block if need be. I used a mk1 A-arm bush which is rubber but high density and solid, and not prone to move much.
http://www.vwwatercooled.com.au/foru...dpbfj4lh-1.jpg
http://www.vwwatercooled.com.au/foru...vipmhxeh-1.jpg
http://www.vwwatercooled.com.au/foru...u1pe0yrg-1.jpg

So the first drive. I was expecting to hear some chatter during slow car-park speed turning. That’s the common complaint from clutch-type LSDs, and the older Kaaz units. There was none at all. I could feel a slight on-off slipping sensation during one maneuverer, but after that I didn’t even notice that feeling again. It seemed like the steering wheel snaps back to centre more, not sure if that’s my imagination. Overall it doesn’t feel bad on the street at all! You’d be hard-pressed to know it had a plate-type diff. Cruising around you wouldn’t. I’m still running in the box so I can’t go nuts yet, but that alone has made me happy. I’m dying to actually try the diff out but I have to be patient.

Only a few weeks to the nats!

Do you want to sell your old diff?

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Originally Posted by Water Boy

Do you want to sell your old diff?

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I will, but I'd want to sell it complete with the gearbox its still in. But first I just have to confirm that the new diff is at least as good as the peloquin on the track which I will know in 2 weeks at the nationals. It better be! Funnily enough the 02A with the peloquin is actually a CDA which I bet is the exact code that you have in your cupra - its out of one. Something to think about ;)

A few videos from yesterdays supersprint at Sydney Motorsport Park South Circuit. This was my first time there. Quite a short tight circuit so you can't really stretch the legs much here. There were a lot of spins, and even a couple of cars into walls - it was a challenging track. The fast uphill corner was exciting to drive and spectate though with plenty of twitching and stepping out. You really can't get a sense of the steepness of some sections in the videos.






I'm very happy with how the car is going. The gearbox/diff is an improvement, I felt like I had more traction and the car felt really stable. I'll have to take it to Wakefield to better compare it to the old one though.

Very impressive, loved the way you carved up the traffic.

You seem to make up a lot of ground under braking. What's your current braking setup?

Thanks, the grouping of cars by performance left a bit to be desired this time. They didn't seem to re-shuffle the groups either. Brakes are 280mm up front with wilwood 4-pot calipers. And a mk2 disc setup on the rear. The brake ventilation setup seems to help too.